Abstract

Abstract

Nitrogen, irrigation, and soil-temperature regime are major factors influencing crop growth. Hot season crops in tropical areas are reported to benefit fom soil temperature reductions caused by straw mulching. But how the mulch would affect the nitrogen and irrigation requirements of the crop is not known. We studied the independent and combined effects of two rates of straw mulch, viz., O and 6 metric tons/ha; three rates of nitrogen, viz., 50, 100, and 150 kg N/ha; and three levels of irrigation, viz., 7.5 cm irrigations based on irrgation water (IW)/pan-evaporation (PAN-E) ratios of 0.6, 0.9, and 1.2 on forage corn (Zea mays L.) in a 2-year field experiment.

Green and dry forage yields and uptake of N and P significantly increased with mulching and with each successive increment of nitrogen. As the IW/PE ratio increased from 0.6 to 0.9 the green and dry forage yields and nutrient uptake increased significantly, but declined with further increase in irrigation. As a 2-year average, mulching increased the dry forage yield by 11.8 quintals/ ha or 26% and showed a significant interaction with nitrogen rates. Fifty kg and 100 kg N/ha with mulch yielded as much as 100 kg and 150 kg N/ha without mulch, respectively.

It is indicated that straw mulching in forage corn during hot and dry season increases yield and nutrient uptake and helps economize nitrogen.

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